RESUMO
Venous and arterial walls are responsive to sympathetic system and circulating substances, nevertheless, very few is known about the venous blood flow regulation simultaneously to arterial vascular beds. In this study, we compared the venous and arterial blood flow regulation in visceral and muscular beds upon injection of different doses of vasoactive drugs which act in arterial vascular beds. Anesthetized adult male Wistar rats underwent to right femoral artery and vein cannulation for hemodynamic recordings and infusion of drugs. Doppler flow probes were placed around the left renal artery and vein, and left femoral artery and vein to evaluate the changes in flood flow. Phenylephrine (PHE) injection (α1-adrenergic receptor agonist) elicited vasoconstriction in all arteries and veins. Intravenous prazosin (PZS) (1mg/kg, α1-adrenergic receptor blocker) caused renal artery vasodilation, but not in the other beds. Vasoconstrictor effect of PHE was abolished by PZS in all vascular beds, except in femoral vein. Phentolamine (PTL) injection (1mg/kg, α1/α2-adrenergic receptor blocker) produced renal artery vasodilation with no change in other beds. After PTL, the vasoconstriction evoked by PHE was abolished in all vascular beds. Sodium Nitroprusside (SNP), a nitric oxide donor, elicited vasodilation in all beds, and after PTL but not post PZS injection, SNP enhanced the vasodilatory effect in femoral vein. Our findings suggest that the vasoconstriction in renal and femoral veins is mediated by different subtypes of α-adrenoceptors. The nitric oxide-dependent vasodilation in femoral vein enhances when α2-adrenoceptors are not under stimulation, but not in the other vascular beds investigated.
Assuntos
Veia Femoral/metabolismo , Hemodinâmica , Óxido Nítrico/metabolismo , Receptores Adrenérgicos alfa/metabolismo , Circulação Renal , Veias Renais/metabolismo , Adrenérgicos/administração & dosagem , Animais , Velocidade do Fluxo Sanguíneo , Veia Femoral/efeitos dos fármacos , Hemodinâmica/efeitos dos fármacos , Injeções Intravenosas , Masculino , Doadores de Óxido Nítrico/administração & dosagem , Ratos Wistar , Receptores Adrenérgicos alfa/efeitos dos fármacos , Fluxo Sanguíneo Regional , Circulação Renal/efeitos dos fármacos , Veias Renais/efeitos dos fármacos , Transdução de Sinais , Vasoconstrição , Vasoconstritores/administração & dosagem , Vasodilatação , Vasodilatadores/administração & dosagemRESUMO
Vancomycin (VCM) is indicated in combat against Gram-positive infections, but it is not considered a first-choice drug because of its adverse effects. It is believed that oxidative stress is the primary mechanism of endothelial injury and the consequent VCM toxicity, which varies from phlebitis to nephrotoxicity. Moreover, dose recommendations, dilution, rates and types of infusion are still controversial. The aim of this study was to determine the effect of different VCM dilutions in endothelial, liver and kidney injuries by biochemical parameters and histopathological analysis. Wistar rats were randomly divided into six groups and subjected to femoral vein cannulation for drug administration. Control groups received 0.9 ml of saline and the others received VCM (10mg/Kg/day) at dilutions of 5.0 and 10.0 mg/mL for 3 and 7 days. Homocysteine, hs-CRP, AST, ALT, GGT, urea, creatinine, lycopene, alpha-tocopherol, beta-carotene and retinol were analyzed. Kidney, liver and cannulated femoral vein fragments were collected.This study showed alterations in ALT which featured hepatotoxicity. However, drug dilutions were not able to show changes in other biochemical parameters. In contrast, kidney and endothelium pathological changes were observed. More studies are needed to characterize VCM induced kidney and endothelium toxicity and biochemical markers able to show such morphological modifications.
Assuntos
Antibacterianos/toxicidade , Veia Femoral/efeitos dos fármacos , Rim/efeitos dos fármacos , Rim/patologia , Fígado/efeitos dos fármacos , Vancomicina/toxicidade , Animais , Relação Dose-Resposta a Droga , Veia Femoral/metabolismo , Veia Femoral/patologia , Rim/metabolismo , Fígado/metabolismo , Fígado/patologia , Masculino , Distribuição Aleatória , Ratos WistarRESUMO
Com o objetivo de avaliar o comportamento de três tipos de prótese, veia safena, PTFE expandido e veia umbilical humana, em revascularizaçäo de membro inferior abaixo do joelho, foi feito levantamento retrospectivo de 190 casos operados. Em 106, as pontes eram femoro-poplíteas e em 84 eram femoro-tibiais pu peroneiras. Quanto as pontes femoro-poplíteas infra-patelares, a perviedade cumulativa após 9 anos foi de 67,6% nos casos em que se utilizou veia safena. A perviedade cumulativa nos casos em que se usou veia umbilical humana preservada foi de 60% ao cabo de três anos. Nos casos em que foi utilizado o PTFE, a perviedade a final de 5 anos foi de 47,8%. Quanto as pontes femoro-tibiais ou peroneiras, a perviedade cumulativa dos enxertos de veia safena foi de 58% após 6 anos. Nos casos em que foi utilizada veia umbilical humana preservada, a perviedade cumulativa foi de 50,5% após 3 anos e, após 4 anos a perviedade cumulativa dos enxertos de PTFE foi de 24%. Conclui-se que a veia safena é a prótese de eleiçäo nas revascularizaçöes em posiçäo crítica. Os resultados obtidos com a veia umbilical, a tornam substituto adequado nestas posiçöes, enquanto que o PTFE näo apresenta resultados esperados nas revascularizaçöes distais